NEW YORK — As expected, the Mets placed outfielder Jason Bay on the disabled list. He was put on the seven-day concussion disabled list but manager Terry Collins said he expects Bay to be sidelined longer than that.

Although veteran Manny Ramirez is available after being released by Oakland on Friday, Collins said the team isn’t looking to add any outfielders in Bay’s absence.

Bay, who slid headfirst into the left-field wall in Friday night’s game against the Reds trying to make a catch on Jay Bruce’s second-inning inside-the-park home run, was told by doctors to remain home for the next few days and rest.

It was the second concussion suffered by Bay in less than two years — he suffered one on Aug. 23, 2010, when he crashed into a wall in Los Angeles. He missed the rest of the season.

“I’m very worried because Jason’s first one was pretty severe, and he hit that wall pretty hard (Friday night),” Collins said. “He’s pretty sore, real sore.

“I don’t know how long it’s going to be, but my guess is it is certainly going to take a little bit of time,” said Collins regarding Bay’s return.

Bay, who signed a four-year, $66 million deal prior to the 2010 season, is making his fourth trip to the disabled list in his 2½ seasons with the Mets.

He’s hitting just .187 with four homers and six RBI this season.

The plan is for Hairston to replace Bay primarily against left-handers. Against right-handers, Andres Torres will play center field, with Kirk Nieuwenhuis shifting from center field to left field.

• Although each team plunked a player again — the Reds’ Jay Bruce and the Mets’ Lucas Duda were hit — Collins didn’t see any intent. Unlike Friday night.
“Not today,” Collins said. “I don’t think it was intentional at all.”

The Reds’ Joey Votto and the Mets’ David Wright were hit by pitches Friday night.

• Ike Davis went 1-for-4 to extend his hitting streak to a modest seven games. He’s now hitting .192.

Duda, who was 1-for-3, has reached base safety in a career-high 19 consecutive games.

• Though Justin Turner (sprained ankle) had just eight at-bats at Triple-A Buffalo during a rehab assignment, he was recalled to replace the injured Bay.

Collins previously had said he preferred to have players get at least 20 at-bats during their rehab assignments from injuries at the Triple-A level before returning to the big club.

But with Bay’s injury, Collins has altered his thinking.

“He really gives us a very good option of a guy off the bench who can handle the bat,” Collins explained.

Turner, who was placed on the disabled list with a sprained right ankle May 29, will primarily pinch-hit because he’s still experiencing some morning soreness in his ankle.

• Ruben Tejada (right quad strain) had been running in a straight line and was scheduled to begin running in a semicircle Saturday. Collins said the plan is to play him in a rehab game Monday.